The present invention relates to a pouch comprising a flexible bag having an opening at one end, and a safety valve arranged inside the bag to substantially prevent the content of the bag from leaving through the opening.
Pouches of this type are known, e.g. from European patents Nos. 0 748 620 or 0 847 742. They are used to receive substances generally in liquid form, in particular waste of human or animal origin such as urine or vomit.
Such pouches are commonly made from thin sheets of plastics material (e.g. polyethylene) or of other flexible materials. They include a safety valve arranged inside the bag to substantially prevent the content of the bag leaving through the opening, e.g. when the pouch is accidentally turned upside-down.
Such a valve comprises at least two nested pairs of sheets that are locally bonded together at a plurality of bonding points which are aligned parallel to and in the vicinity of one of the (rectilinear or substantially rectilinear) distal end and which are equally spaced. For example, the sheets are thin sheets of plastics material, and the aligned bonding points are made by locally melting the plastics material.
With such a configuration, a liquid trapped in the bag cannot in principle leave the space between the walls of the bag and the outer pair of sheets of the valve. Furthermore, since the valve has a plurality of overlapping pairs of sheets, if a small quantity of liquid penetrates between the outer pair of sheets and the pair of sheets nested within, the liquid will tend to remain trapped between these two pairs of sheets.
After numerous tests relating to the arrangement of the bonding points, the inventor has identified the fact that the spacing between the bonding points plays a crucial role in the operation of the valve.
Specifically, the arrangement of the bonding points needs to be selected in such a manner as to obtain a good compromise between two conflicting objectives: firstly, facilitating the passage of the liquid when it is inserted into the pouch, and secondly, impeding or preventing the passage of the liquid after it has been trapped in the bag.
The inventor has discovered that the valve's ability to impede or prevent the passage of the liquid trapped in the pouch depends on the spacing between the bonding points in the direction parallel to the opening, i.e. in the direction perpendicular to the direction in which liquid is inserted into the pouch.
However, in pouches of the type mentioned above, the bonding points are merely aligned parallel to the distal end of the sheets, and the spacing between the bonding points in the direction perpendicular to the direction for inserting liquid is small, so as to limit leaks of the liquid trapped in the bag.
That configuration presents drawbacks.
Indeed, the small spacing between the bonding points tends to limit the passage of the liquid while it is being inserted into the pouch, which may impede proper use of the pouch.
Furthermore, when the liquid contains solid elements (solid elements in vomit, clots of blood in urine, etc.), the bonding points can impede or even prevent those solid elements from passing through.